code: def set_backend(backend):
      """
      Set utils.audio_utils' backend module.
      If the backend which you specify is not installed in your environment, Exception is raised.
  
      Args:
          backend (str): the name of audio_utils' backend
      """
  
      backend_manager.backend = backend
  
file_path: nnabla/python/src/nnabla/utils/audio_utils/__init__.py
imports: from __future__ import absolute_import
  import numpy
  from .backend_manager import backend_manager
  from .common import rescale_intensity, _auto_scale_before
label_desc: Use image node_id 1 for calling a global function with example usage: set_backend(backend) without return types